1c221c0b0SDave Hansen // SPDX-License-Identifier: GPL-2.0 2c221c0b0SDave Hansen /* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */ 3c221c0b0SDave Hansen #include <linux/memremap.h> 4c221c0b0SDave Hansen #include <linux/pagemap.h> 5c221c0b0SDave Hansen #include <linux/memory.h> 6c221c0b0SDave Hansen #include <linux/module.h> 7c221c0b0SDave Hansen #include <linux/device.h> 8c221c0b0SDave Hansen #include <linux/pfn_t.h> 9c221c0b0SDave Hansen #include <linux/slab.h> 10c221c0b0SDave Hansen #include <linux/dax.h> 11c221c0b0SDave Hansen #include <linux/fs.h> 12c221c0b0SDave Hansen #include <linux/mm.h> 13c221c0b0SDave Hansen #include <linux/mman.h> 14c221c0b0SDave Hansen #include "dax-private.h" 15c221c0b0SDave Hansen #include "bus.h" 16c221c0b0SDave Hansen 17c221c0b0SDave Hansen int dev_dax_kmem_probe(struct device *dev) 18c221c0b0SDave Hansen { 19c221c0b0SDave Hansen struct dev_dax *dev_dax = to_dev_dax(dev); 20c221c0b0SDave Hansen struct resource *res = &dev_dax->region->res; 21c221c0b0SDave Hansen resource_size_t kmem_start; 22c221c0b0SDave Hansen resource_size_t kmem_size; 23c221c0b0SDave Hansen resource_size_t kmem_end; 24c221c0b0SDave Hansen struct resource *new_res; 25c221c0b0SDave Hansen int numa_node; 26c221c0b0SDave Hansen int rc; 27c221c0b0SDave Hansen 28c221c0b0SDave Hansen /* 29c221c0b0SDave Hansen * Ensure good NUMA information for the persistent memory. 30c221c0b0SDave Hansen * Without this check, there is a risk that slow memory 31c221c0b0SDave Hansen * could be mixed in a node with faster memory, causing 32c221c0b0SDave Hansen * unavoidable performance issues. 33c221c0b0SDave Hansen */ 34c221c0b0SDave Hansen numa_node = dev_dax->target_node; 35c221c0b0SDave Hansen if (numa_node < 0) { 36c221c0b0SDave Hansen dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n", 37c221c0b0SDave Hansen res, numa_node); 38c221c0b0SDave Hansen return -EINVAL; 39c221c0b0SDave Hansen } 40c221c0b0SDave Hansen 41c221c0b0SDave Hansen /* Hotplug starting at the beginning of the next block: */ 42c221c0b0SDave Hansen kmem_start = ALIGN(res->start, memory_block_size_bytes()); 43c221c0b0SDave Hansen 44c221c0b0SDave Hansen kmem_size = resource_size(res); 45c221c0b0SDave Hansen /* Adjust the size down to compensate for moving up kmem_start: */ 46c221c0b0SDave Hansen kmem_size -= kmem_start - res->start; 47c221c0b0SDave Hansen /* Align the size down to cover only complete blocks: */ 48c221c0b0SDave Hansen kmem_size &= ~(memory_block_size_bytes() - 1); 49c221c0b0SDave Hansen kmem_end = kmem_start + kmem_size; 50c221c0b0SDave Hansen 51c221c0b0SDave Hansen /* Region is permanently reserved. Hot-remove not yet implemented. */ 52c221c0b0SDave Hansen new_res = request_mem_region(kmem_start, kmem_size, dev_name(dev)); 53c221c0b0SDave Hansen if (!new_res) { 54c221c0b0SDave Hansen dev_warn(dev, "could not reserve region [%pa-%pa]\n", 55c221c0b0SDave Hansen &kmem_start, &kmem_end); 56c221c0b0SDave Hansen return -EBUSY; 57c221c0b0SDave Hansen } 58c221c0b0SDave Hansen 59c221c0b0SDave Hansen /* 60c221c0b0SDave Hansen * Set flags appropriate for System RAM. Leave ..._BUSY clear 61c221c0b0SDave Hansen * so that add_memory() can add a child resource. Do not 62c221c0b0SDave Hansen * inherit flags from the parent since it may set new flags 63c221c0b0SDave Hansen * unknown to us that will break add_memory() below. 64c221c0b0SDave Hansen */ 65c221c0b0SDave Hansen new_res->flags = IORESOURCE_SYSTEM_RAM; 66c221c0b0SDave Hansen new_res->name = dev_name(dev); 67c221c0b0SDave Hansen 68c221c0b0SDave Hansen rc = add_memory(numa_node, new_res->start, resource_size(new_res)); 69c221c0b0SDave Hansen if (rc) 70c221c0b0SDave Hansen return rc; 71c221c0b0SDave Hansen 72c221c0b0SDave Hansen return 0; 73c221c0b0SDave Hansen } 74c221c0b0SDave Hansen 75c221c0b0SDave Hansen static int dev_dax_kmem_remove(struct device *dev) 76c221c0b0SDave Hansen { 77c221c0b0SDave Hansen /* 78c221c0b0SDave Hansen * Purposely leak the request_mem_region() for the device-dax 79c221c0b0SDave Hansen * range and return '0' to ->remove() attempts. The removal of 80c221c0b0SDave Hansen * the device from the driver always succeeds, but the region 81c221c0b0SDave Hansen * is permanently pinned as reserved by the unreleased 82c221c0b0SDave Hansen * request_mem_region(). 83c221c0b0SDave Hansen */ 84c221c0b0SDave Hansen return 0; 85c221c0b0SDave Hansen } 86c221c0b0SDave Hansen 87c221c0b0SDave Hansen static struct dax_device_driver device_dax_kmem_driver = { 88c221c0b0SDave Hansen .drv = { 89c221c0b0SDave Hansen .probe = dev_dax_kmem_probe, 90c221c0b0SDave Hansen .remove = dev_dax_kmem_remove, 91c221c0b0SDave Hansen }, 92c221c0b0SDave Hansen }; 93c221c0b0SDave Hansen 94c221c0b0SDave Hansen static int __init dax_kmem_init(void) 95c221c0b0SDave Hansen { 96c221c0b0SDave Hansen return dax_driver_register(&device_dax_kmem_driver); 97c221c0b0SDave Hansen } 98c221c0b0SDave Hansen 99c221c0b0SDave Hansen static void __exit dax_kmem_exit(void) 100c221c0b0SDave Hansen { 101c221c0b0SDave Hansen dax_driver_unregister(&device_dax_kmem_driver); 102c221c0b0SDave Hansen } 103c221c0b0SDave Hansen 104c221c0b0SDave Hansen MODULE_AUTHOR("Intel Corporation"); 105c221c0b0SDave Hansen MODULE_LICENSE("GPL v2"); 106c221c0b0SDave Hansen module_init(dax_kmem_init); 107c221c0b0SDave Hansen module_exit(dax_kmem_exit); 108c221c0b0SDave Hansen MODULE_ALIAS_DAX_DEVICE(0); 109